(A) Field of the Invention
The present invention relates to cigarette products, and more particularly to a filter for a cigarette product and a method for making the filter.
(B) Description of the Prior Art
When filter cigarettes were first introduced, it was a common and acceptable practice to wrap the filter tow or plug with a non-porous wrapper. The wrapper was held in place or attached to the filter plug by a line of adhesive. However, with the advent of a porous filter plug wrap, it was found that the adhesive anchoring of the porous plug wrap to the filter plug would penetrate the porous wrap causing an adhesive build-up in critical areas of the filter rod making machines. This resulted in a substantial amount of down-time to periodically clean the filter rod making machines. In addition, as adhesive build-up occurred, the quality of the manufacture of filter rods was adversely affected. To solve this problem, the line of adhesive for anchoring the porous filter wrap to the filter plug was eliminated. However, due to the elimination of the anchoring line of adhesive, it has become common to experience filter cigarettes wherein the filter plug has moved relative to the filter wrap and is recessed into the filter wrap.
In recent years, it has been suggested that a film forming substance be first applied to the filter wrap at a location or locations therealong coinciding with a region or regions at which adhesives are to be applied to create an impervious barrier to the adhesive. Two patents which relate to the present problem are U.S. Pat. No. 4,036,114 and U.S. Pat. No. 3,298,353.